We are still looking for help with this issue, here is what we have so far:
Number of ideas submitted -- Using metrics Net Ideas
Number of kudo submitted -- Using REST api - /boards/id/<id>/kudos/count we can fetch total kudos for each Ideas board and tally.
Number of comments posted -- Using metrics Net Ideas Comments
Number of ideas implemented -- No solution found ( we can't see anything in the metrics? )
We've looked at the REST call
/board/id/<id>/threads/for/message_statuses/id/<implemented> .. /top/count .. /recent/count ../popular/count
But we are after a count for ALL "Implemented" Ideas to date.